Webbing retracting device

ABSTRACT

A webbing retracting device that may prevent entering of an end-lock state when a spool rotates in the pull out direction on rebound just after completion of taking up of the webbing belt. A restriction weight is provided on a V gear. The restriction weight moves in the pull out direction relative to the V gear by acceleration when the V gear is rotated in the take up direction, and furthermore, the restriction weight pivots about a support pin under centrifugal force due to rotation of the V gear and attains a contact position. In such a state, even if the inertial mass attempts to displace toward the lock activation direction, the restriction weight interferes with the inertial mass and restricts displacement of the inertial mass toward the lock activation direction.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.11/765,144 filed on Jun. 19, 2007, which claims priority under 35 U.S.C.119 from Japanese Patent Applications No. 2006-170536 and No.2006-343277, all of which are incorporated by reference herein.

BACKGROUND

1. Technical Field

The present invention is related to a webbing retracting device fortaking up and storing a webbing belt for restricting the body of avehicle occupant sitting in a seat.

2. Related Art

In webbing retracting devices that configure vehicle seat belt devicesthere are lock mechanisms provided that restrict rotation of a reelshaft in a pull out direction when a vehicle suddenly decelerates, forexample as described in Japanese Patent Application Laid-open (JP-A) No.05-193441 (Patent Publication 1). A lock gear configuring the lockmechanism described in Patent Publication 1 is coaxially rotatablerelative to the reel shaft, and when the reel shaft rotates in the pullout direction relative to the lock gear, coupled to this relativerotation, the teeth of each of a main pawl and a backup pawl mesh withinternal teeth formed on both side walls of a frame, and rotation of thereel shaft in the pull out direction is restricted. There are two typesof configuration for generating relative rotation between the reel shaftand the lock gear, one being a deceleration detecting means. Thedeceleration detecting means is provided with an inertial body thatmoves with inertia when a vehicle suddenly decelerates, and an engagingpawl, pushed up by an inertially moved inertial body, engages withexternal teeth on the lock gear, thereby restricting rotation of thelock gear, and the lock gear rotates relative to the reel shaft that isrotating in the pull out direction.

Another configuration for generating relative rotation between the reelshaft and the lock gear is another inertial body, separate to theinertial body of the deceleration detection means, provided on the lockgear. This inertial body is connected to the lock gear by a spring, butwhen the reel shaft together with the lock gear suddenly rotates in thepull out direction, a rotational lag occurs of this inertial bodyagainst the biasing force due to the spring and relative to the lockgear. Along with the rotation relative to the lock gear due to therotational lag, the inertial body moves to the outside in the rotationalradial direction of the lock gear, and meshes with inner ratchet teeththat are formed on the inside of a cover, and rotation of the inertialbody, and therefore rotation of the lock gear, is stopped. In thismanner, by stopping the rotation of the lock gear, the lock gear rotatesrelative to the reel shaft that is rotating in the pull out direction.

However, just after completion of taking up the webbing belt by the reelshaft if the lock mechanism is unintentionally actuated, then the reelshaft is not able to rotate in the pull out direction from this state,entering a so-called “end-lock state”. In such an end-lock state, sincethe reel shaft is not able to rotate in the pull out direction, pullingout of the webbing belt becomes difficult. Therefore, in the abovePatent Publication 1, when taking up of the webbing belt is competed itis configured such that the external teeth of the lock gear and theengagement pawl of the deceleration detection means do not meshtogether, so as to prevent an end-lock state arising.

SUMMARY

In consideration of the above circumstances, the present inventionprovides a webbing retracting device that can prevent an end-lock statearising when a spool rotates in the pull out direction due to a rebound(reaction) just after taking up of the webbing belt is stopped.

A first aspect of the present invention is a webbing retracting deviceincluding: a spool that, by rotation in a take up direction, takes up alongitudinal band-shaped webbing belt from a base end side of webbingbelt and stores the webbing belt thereon; a rotational body provide soas to be able to rotate relative to the spool and connected to the spoolso as to be able to rotate to follow rotation of the spool; a lockmember that restricts rotation of the spool in a pull out direction byactivation thereof; a rotation detection member, provided at therotational body, that is displaced toward a predetermined lockactivation direction to activate the lock member when the rotationalbody rotates in the pull out direction at a predetermined velocity orgreater; and a restriction unit, provided at the rotational body, thatrestricts displacement of the rotation detection member toward the lockactivation direction due to a rebound by stopping of taking up of thewebbing belt to the spool.

According to the webbing retracting device according to the first aspectof the present invention, when the spool rotates to the take updirection side, the webbing belt is taken up and stored on the spoolfrom the side of the longitudinal direction base end thereof. When thetaking up of the webbing belt by the spool stops and the spool stopsabruptly, with a rebound thereof the rotational body that rotatesfollowing the spool sometimes rotates suddenly, and by a small amount,in the pull out direction. The webbing retracting device of the presentinvention basically couples the sudden rotation of the rotational bodyin the pull out direction, the rotation detection member is displaced inthe lock activation direction, and due to this the lock member locks thespool and restricts rotation of the spool in the pull out direction.

However, in the webbing retracting device of the present invention, whensudden rotation of the rotational body in the pull out direction is dueto a rebound, when the spool stops taking up of the webbing belt, thendisplacement of the rotation detection member toward the lock activationdirection is restricted by the restriction unit, and in such a case thelock member does not restrict rotation of the spool in the pull outdirection (the so-called “end-lock state” does not arise). Therefore,the webbing belt may be easily pulled out once again.

A second aspect of the present invention is the webbing retractingdevice according to the first aspect of the present invention, furtherincluding a prevention member that, in a state in which the rotationalbody is rotating in the pull out direction, which is different from astate in which the rotational body is rotated in the pull out directioncaused by the rebound by stopping of taking up of the webbing belt,prevents restricting, by the restriction unit, of the displacement ofthe rotation detection member toward the lock activation direction.

According to the webbing retracting device according to the secondaspect of the present invention, when the rotational body is in a staterotating in the pull out direction that is not when the taking up of thewebbing belt has stopped, then restriction by the restriction unit ofdisplacement of the rotation detection member toward the lock activationdirection is prevented by the prevention member. Due to this, by thatthe body of an occupant moves in a direction substantially to the frontof a vehicle, due to inertia as the vehicle decelerates, and therebysuddenly the webbing belt is pulled by the body of the occupant, whenthe rotational body together with the spool suddenly rotates in the pullout direction, the rotation detection member can displace in the lockactivation direction, and rotation of the spool in the pull outdirection can be restricted by actuation of the lock member.

A third aspect of the present invention is the webbing retracting deviceaccording to the first aspect or the second aspect of the presentinvention wherein: the restriction unit is provided so as to be movablebetween a contact position, in which the restriction unit is in contactwith the rotation detection member and is able to restrict displacementof the rotation detection member to the lock activation direction, and anon contact position, which is separated from the contact position andwhich allows displacement of the rotation detection member toward thelock activation direction; and the restriction unit displaces to thecontact position by rotation of the rotational body in the take updirection.

According to the webbing retracting device according to the third aspectof the present invention, the restriction unit is separated from the noncontact position by the rotation of the rotational body in the take updirection. In doing so the restriction unit can be moved to the contactposition. In the state just after rotation of the spool in the take updirection has stopped, the restriction unit is positioned in the contactposition, From this state, the restriction unit contacts with therotation detection member and restricts displacement of the rotationdetection member, if the rotation detection member attempts to displacetoward the lock activation direction by sudden rotation of therotational body, by a small amount, in the pull out direction.

Here, as described above, since the restriction unit is configured toseparate from the non contact position by rotation of the rotationalbody in the take up direction, basically (that is to say if it is not acase in which the rotational body rotates in the pull out direction by arebound when the spool has stopped taking up of the webbing belt), ifthe rotational body rotates in the pull out direction, there is noseparation of the restriction unit from the non contact position, andtherefore the restriction unit does not attain the contact position.Therefore, when the spool rotates in the pull out direction in normaloperation and also when the spool rotates in the pull out direction asthe vehicle suddenly decelerates and the rotational body rotates in thepull out direction, there is no movement of the restriction unit to thecontact position, and the restriction unit does not unintentionallyinterfere with the displacement of the rotation detection member.

A fourth aspect of the present invention is the webbing retractingdevice according to the third aspect of the present invention, whereinthe restriction unit in the non contact position is moved to the contactposition by centrifugal force by the rotating of rotational body.

According to the webbing retracting device according to the fourthaspect of the present invention, the restriction unit, which is in thenon contact position, and thereafter, which is separated from the noncontact position by the acceleration of the rotational body in the takeup direction, moves toward the contact position due to the centrifugalforce by the rotation of the rotational body. The restriction unit thatis moved in this manner, in the state of having attained the contactposition, contacts with the rotation detection member and restrictsdisplacement of the rotation detection member, when the rotationdetection member attempts to displace in the lock activation directionby the sudden rotation, by a small amount, of the rotational body in thepull out direction just after the rotation of the spool stops in thetake up direction.

A fifth aspect of the present invention is the webbing retracting deviceaccording to the third aspect or the fourth aspect, wherein therestriction unit in the non contact position is moved to the contactposition by generation of a frictional force by the rotation of therotational body.

According to the webbing retracting device according to the fifth aspectof the present invention, the restriction unit in the non contactposition is moved to the contact position by a frictional forcegenerated by rotation of the rotational body. The restriction unit movedin this manner in the state of having attained the contact position,contacts with the rotation detection member and restricts displacementof the rotation detection member, when the rotation detection memberattempts to displace in the lock activation direction by the suddenrotation, by a small amount, of the rotational body in the pull outdirection just after the rotation of the spool stops in the take updirection.

A sixth aspect of the present invention is the webbing retracting deviceaccording to one of the third aspect to the fifth aspect, furtherincluding a biasing member that biases the restriction unit from thecontact position toward the non contact position.

According to the webbing retracting device according to the sixth aspectof the present invention, the restriction unit is biased by the biasingmember in the direction from the contact position toward the non contactposition. Due to this, the restriction unit that has attained thecontact position, after restricting the displacement of the rotationdetection member toward the lock activation direction, then returns tothe non contact position by the biasing force of the biasing member.

A seventh aspect of the present invention is the webbing retractingdevice according to the sixth aspect, wherein the biasing member biasesthe rotation detection member in the opposite direction to the lockactivation direction.

According to the webbing retracting device according to the seventhaspect of the present invention, the rotation detection member is biasedby the biasing member in the opposite direction to the lock activationdirection. Due to this, when rotation of the rotational body in the pullout direction, at a predetermined velocity or greater, ceases, therotation detection member that has been displaced in the lock activationdirection is displaced in the opposite direction to the lock activationdirection by the biasing force of the biasing member, and returns to theoriginal state. Due to this, the restriction on the rotation of thespool by the lock member is thus released.

Here, in the webbing retracting device according to the presentinvention, the biasing member biases the rotation detection member inthe opposite direction to the lock activation direction, and also biasesthe restriction unit in the direction from the contact position towardthe non contact position, therefore the biasing of the rotationdetection member and the biasing of the restriction unit is by a singlecomponent, and the number of components may thereby be reduced.

An eighth aspect of the present invention is the webbing retractingdevice according to one of the first aspect to the seventh aspectfurther including an additional biasing member that biases the rotationdetection member in the opposite direction to the lock activationdirection.

According to the webbing retracting device according to the eighthaspect of the present invention, the additional biasing member biasesthe rotation detection member in the opposite direction to the lockactivation direction. Therefore, the rotation detection member can bebiased appropriately in the opposite direction to the lock activationdirection.

A ninth aspect of the present invention is the webbing retracting deviceaccording to one of the first aspect to the eighth aspect, wherein therestriction unit includes: a moving member that is moved by the reboundwhen taking up of the webbing belt to the spool stops; and a restrictionmember that is moved by the movement of the moving member and restrictsdisplacement of the rotation detection member toward the lock activationdirection.

According to the webbing retracting device according to the ninth aspectof the present invention, the restriction unit includes a moving memberand a restriction member, and by the moving member moving, due to therebound when taking up of the webbing belt to the spool stopping, therestriction member is moved, and displacement of the rotation detectionmember toward the lock activation direction is restricted. Therefore,the restriction unit can be appropriately actuated.

A tenth aspect of the present invention is the webbing retracting deviceaccording to any one of the first aspect to the eighth aspect, whereinthe restriction unit includes: a friction force generation member thatgenerates a friction force due to rotation of the rotational body and ismoved; and a displacement restriction member that is moved by movementof the friction force generation member and restricts displacement ofthe rotation detection member toward the lock activation direction.

According to the webbing retracting device according to the tenth aspectof the present invention, the restriction unit includes a friction forcegeneration member and a displacement restriction member, and thefriction force generation member generates a frictional force due torotation of the rotational body and is moved, thereby the displacementrestriction member is moved, and the rotation detection member isrestricted from displacement to the lock activation direction.Therefore, the restriction unit may be appropriately actuated.

An eleventh aspect of the present invention is a webbing retractingdevice including: a spool that, by rotation in a take up direction,takes up a longitudinal band-shaped webbing belt from a base end side ofwebbing belt and stores the webbing belt thereon; a rotational bodyprovide so as to be able to rotate relative to the spool and connectedto the spool so as to be able to rotate to follow rotation of the spool;a lock member that restricts rotation of the spool in a pull outdirection by activation thereof; a rotation detection member, providedat the rotational body, that is displaced toward a predetermined lockactivation direction to activate the lock member when the rotationalbody rotates in the pull out direction at a predetermined velocity orgreater; and a restriction unit, provided at the rotational body, thatrestricts displacement of the rotation detection member toward the lockactivation direction due to a rebound by stopping of taking up of thewebbing belt to the spool, wherein the restriction unit is activated byinertia thereof and centrifugal force generated by the rotating ofrotational body.

A twelfth aspect of the present invention is a webbing retracting deviceincluding: a spool that, by rotation in a take up direction, takes up alongitudinal band-shaped webbing belt from a base end side of webbingbelt and stores the webbing belt thereon; a rotational body provide soas to be able to rotate relative to the spool and connected to the spoolso as to be able to rotate to follow rotation of the spool; a lockmember that restricts rotation of the spool in a pull out direction byactivation thereof; a rotation detection member, provided at therotational body, that is displaced toward a predetermined lockactivation direction to activate the lock member when the rotationalbody rotates in the pull out direction at a predetermined velocity orgreater; and a restriction unit, provided at the rotational body, thatrestricts displacement of the rotation detection member toward the lockactivation direction due to a rebound by stopping of taking up of thewebbing belt to the spool, wherein the restriction unit is activated bygeneration of a frictional force by the rotation of the rotational body.

As explained above, the webbing retracting device according to thepresent invention can extremely effectively prevent the so-calledend-lock state even if, just after stopping taking up the webbing belt,the spool rotates in the pull out direction with the rebound thereto.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention will be described indetail based on the following figures, wherein:

FIG. 1 is an exploded perspective view showing a configuration of awebbing retracting device according to a first exemplary embodiment ofthe present invention;

FIG. 2 is an exploded perspective view showing a configuration ofrelevant portions of a webbing retracting device according to the firstexemplary embodiment of the present invention;

FIG. 3 is a front view of a rotational body, a rotation detectionmember, a restriction unit, and a prevention member in a webbingretracting device according to the first exemplary embodiment of thepresent invention;

FIG. 4 is a front view, corresponding to FIG. 3, showing a state inwhich a rotation detection member is displaced in the lock activationdirection in a webbing retracting device according to the firstexemplary embodiment of the present invention;

FIG. 5 is a front view, corresponding to FIG. 3, showing a state inwhich displacement of the rotation detection member in the lockactivation direction is restricted by a restriction unit in a webbingretracting device according to the first exemplary embodiment of thepresent invention;

FIG. 6 is an exploded perspective view showing a configuration ofrelevant portions of a webbing retracting device according to a secondexemplary embodiment of the present invention;

FIG. 7 is a front view of a rotational body, a rotation detectionmember, a restriction unit, and a prevention member in a webbingretracting device according to the second exemplary embodiment of thepresent invention;

FIG. 8 is a front view, corresponding to FIG. 7, showing a state inwhich a rotation detection member is displaced in the lock activationdirection in a webbing retracting device according to the secondexemplary embodiment of the present invention;

FIG. 9 is a front view, corresponding to FIG. 7, showing a state inwhich displacement of the rotation detection member in the lockactivation direction is restricted by a restriction unit in a webbingretracting device according to the second exemplary embodiment of thepresent invention;

FIG. 10 is an exploded perspective view showing a configuration ofrelevant portions of a webbing retracting device according to a thirdexemplary embodiment of the present invention;

FIG. 11 is a front view of a rotational body, a rotation detectionmember, and a restriction unit in a webbing retracting device accordingto the third exemplary embodiment of the present invention;

FIG. 12 is a front view, corresponding to FIG. 11, showing a state inwhich a rotation detection member is displaced in the lock activationdirection in a webbing retracting device according to the thirdexemplary embodiment of the present invention;

FIG. 13 is a front view, corresponding to FIG. 11, showing a state inwhich displacement of the rotation detection member in the lockactivation direction is restricted by a restriction unit in a webbingretracting device according to the third exemplary embodiment of thepresent invention;

FIG. 14A is a cross-section showing the rotational body, the rotationdetection member, and the restriction unit in a webbing retractingdevice according to the third exemplary embodiment of the presentinvention, FIG. 14B is a side view showing the restriction unit in awebbing retracting device according to the third exemplary embodiment ofthe present invention;

FIG. 15 is an exploded perspective view of a friction spring and a coverin a webbing retracting device according to the third exemplaryembodiment of the present invention;

FIG. 16 is an exploded perspective view showing a configuration ofrelevant portions of a webbing retracting device according to a fourthexemplary embodiment of the present invention;

FIG. 17 is a front view of a rotational body, a rotation detectionmember, and a restriction unit in a webbing retracting device accordingto the fourth exemplary embodiment of the present invention;

FIG. 18 is a front view, corresponding to FIG. 17, showing a state inwhich a rotation detection member is displaced in the lock activationdirection in a webbing retracting device according to the fourthexemplary embodiment of the present invention;

FIG. 19 is a front view, corresponding to FIG. 17, showing a state inwhich displacement of the rotation detection member in the lockactivation direction is restricted by a restriction unit in a webbingretracting device according to the fourth exemplary embodiment of thepresent invention;

FIG. 20 is a cross-section showing the rotational body, the rotationdetection member, and the restriction unit in a webbing retractingdevice according to the fourth exemplary embodiment of the presentinvention; and

FIG. 21 is a cross-section showing the rotational body, the rotationdetection member, and the restriction unit in a webbing retractingdevice according to the fourth exemplary embodiment of the presentinvention.

DETAILED DESCRIPTION First Exemplary Embodiment Configuration of theFirst Exemplary Embodiment

In FIG. 2 the overall outline configuration of a webbing retractingdevice according to a first exemplary embodiment of the presentinvention is shown through an exploded perspective view.

As is shown in the figure, a webbing retracting device 10 is providedwith a frame 12. The frame 12 is, for example, provided with a backplate 14 that is a plate shape with a thickness direction thereof thatis in the substantially left-right direction of a vehicle. The presentwebbing retracting device 10 is a structure that is attached to avehicle body, by the back plate 14 being fixed with fasteners, such asbolts or the like, for example, to a vehicle body in the vicinity of alower end of a center pillar. A leg plate 16 is formed from one widthdirection side of the substantially vehicle front-rear direction backplate 14, bent around toward the inside in the width direction of thevehicle (substantially the vehicle left-right direction). Also, a legplate 18 is formed at the other width direction side of the back plate14, bent around in the same direction as leg plate 16 is formed.

A spool 20 is provided between the leg plate 16 and the leg plate 18.The spool 20 is formed as a substantially cylindrical shape with anaxial direction that is in the direction along which the leg plate 16and the leg plate 18 face each other. There is an insertion through hole22 formed in the spool 20. Both ends of the insertion through hole 22open to outer peripheral portions of the spool 20, and the shape of theopenings are slit shapes that have length directions in the spool 20axial direction. The insertion through hole 22 is formed so as to avoida through hole 24 that penetrates the axial portion of spool 20, and thebase end side in the length direction of a long band-shaped webbing belt26 is pushed through from one of the opening ends of the insertionthrough hole 22.

At a base end portion in the length-wise direction of the webbing belt26 is formed a cylindrical shaped portion 28, with a through hole in thewidth direction of the webbing belt 26, and, by disposing a detachmentprevention shaft 30 at the inside of the cylindrical shaped portion 28that has been inserted through the insertion through hole 22, when thewebbing belt 26 is pulled toward the distal end side, the base end sideof the webbing belt 26 is prevented from being pulled out of theinsertion through hole 22. The webbing belt 26, prevented fromdetachment from the insertion through hole 22 in such a way, is storedby being taken up by winding up in layers from the base end thereof ontothe outer peripheral portion of the spool 20, by rotation of the spool20 in the take up direction that is one of the directions of rotationaround its own axis.

A bar-shaped torsion shaft 32 having a length direction in the axialdirection of the spool 20 is disposed at the inside of the through hole24. The torsion shaft 32 is connected to the spool 20 in a state inwhich pivoting is prevented inside the spool 20 around the axialrotation direction at the leg plate 18 side. Furthermore, the endportion of the torsion shaft 32 on the leg plate 18 side passes throughthe leg plate 18 and protrudes to the outside of the frame 12.

A spring cover 34 is disposed on the outside of the leg plate 18. Thespring cover 34 is of a case-shape that is open to face the inside ofleg plate 18, and the spring cover 34 is fixed to the leg plate 18 byfasteners such as screws or the like and by fitting together fitmentlugs or the like that are formed on the spring cover 34 or on the legplate 18. A spiral spring 36 is accommodated on the inside of the springcover 34. The spiral spring 36 is of a construction such that there is agradual increase in a biasing force thereof when the inside end in thespiral winding direction is rotationally displaced in a pull outdirection relative to the outside end in the spiral winding direction,the pull out direction being the opposite direction to the above take updirection. The outside end in the spiral winding direction of the spiralspring 36 is anchored at a spring seat 38 that is provided to theopening side of the spring cover spring cover 34.

The spring seat 38 is fixed to the spring cover 34, and the outside endin the spiral winding direction of the spiral spring 36 is connected tothe leg plate 18 (the frame 12) via the spring seat 38 and the springcover 34. Furthermore, an adapter 40 is provided in the vicinity of theinside end in the spiral winding direction of the spiral spring 36. Theinside end in the spiral winding direction of the spiral spring 36 isfixed to an outside peripheral portion of the adapter 40. Furthermore,the leg plate 18 side end portion of the torsion shaft 32 is fittedinto, and fixed to, the axial portion of the adapter 40.

A pretensioner 42 is provided at the outside of the leg plate 16. Thepretensioner 42 is provided with a cylinder 44. A gas generator 46 ismounted to the cylinder 44 at a bottom side portion thereof, and when anon illustrated acceleration sensor detects that a vehicle is in a stateof suddenly decreasing velocity, gas generating agent provided in aninternal portion of the gas generator 46 is ignited. By this action, thegas generating agent burns in an extremely short period of time andinstantaneously generates gas. Gas generated in this way is suppliedinto the cylinder 44 and rapidly raises the internal pressure of thecylinder 44. Due to the internal pressure of the cylinder 44 rapidlyrising, a piston 48 that is accommodated in the cylinder 44 slideswithin the cylinder 44. A rack bar 50 is formed at the piston 48, andthe rack bar 50 slides with the movement of the piston 48 thataccompanies the rise in the internal pressure of the cylinder 44.

Also, a gear case 52 is provided at the vicinity of the opening side ofthe cylinder 44 on the leg plate 16 side, and a cover plate 54 isprovided on the opposite side of the cylinder 44, so as to be able tocover the rack bar 50, which has protruded from the cylinder 44, and soas to retain the cylinder 44 in a state of being fixed to the leg plate16 by screws. Furthermore, a pinion 56 is disposed between the coverplate 54 and the gear case 52. The structure is such that the pinion 56is meshed with the rack teeth of the distal end side of the rack bar 50,and the pinion 56 is also axially rotatably supported by the other endof the torsion shaft 32 that penetrates through the leg plate 16 and thegear case 52, and when the rack bar 50 moves upward the pinion 56rotates in the take up direction.

Also, a clutch 58 is provided on the leg plate 16 side end of the pinion56. The clutch 58 is rotatably axially supported by the torsion shaft32, and, therefore, even when the torsion shaft 32 rotates the clutch 58does not rotate. However, the clutch 58 is engaged with the pinion 56and so when the pinion 56 rotates in the take up direction, a portion ofthe clutch 58 deforms and is connected to the torsion shaft 32.

Also, a lock mechanism 60 is provided on the side of the leg plate 16.The lock mechanism 60 is provided with a sensor holder 62. The sensorholder 62 is formed with a recessed shape that is partially open facingtoward the leg plate 16 side, and the sensor holder 62 is fixed to theleg plate 16. Furthermore, a portion of the cover plate 54 is located tothe inside of the portion opening toward the leg plate 16 side. A sensorcover 64 is provided on the side of the sensor holder 62 that isopposite to the side of the leg plate 16. The sensor cover 64 has fixingclaws or the like provided at outer peripheral portions thereof, andthese fit together with predetermined positions of the sensor holder 62and the sensor cover 64 is mechanically connected to the sensor holder62.

A non illustrated cylindrical shaft receiving portion is formed on thesensor cover 64, rotatably axially supporting a portion at the other endof the torsion shaft 32 that has passed through the sensor holder 62. AV gear 66 is provided, serving as a rotating body, between the sensorholder 62 and the sensor cover 64. The V gear 66 is formed with ashallow bottomed cylindrical shape (or saucer shape) opening facingtoward the sensor cover 64 side, and ratchet teeth are formed at anouter peripheral portion on the V gear 66. The torsion shaft 32 passesthrough the V gear 66, and the V gear 66 is attached to the torsionshaft 32 such that it is able to rotate coaxially and integrally withthe torsion shaft 32.

Here, the configuration between the V gear 66 and the sensor cover 64 ofFIG. 2 is shown in FIG. 1. As shown in FIG. 1, a rotation detectionmechanism 68 is provided on the inside of the V gear 66. The rotationdetection mechanism 68 is provided with a gear ring 70. A low wall 72that is circular shaped when viewed from the front is provided to thegear ring 70. A circular hole 74 is formed at the low wall 72,concentric to the outer peripheral portion thereof. An axial portion 76that is formed at the V gear 66 is passed through at the circular hole74, and the gear ring 70 is axially supported rotatably at the axialportion 76. Furthermore, a ring shaped gear portion 78, formed withinternal ratchet teeth at an inner peripheral portion thereof, is formedcoaxially and integrally to the low wall 72, at the face of the low wall72 on the leg plate 16 side.

A W pawl 80 is provided at the inside of the gear ring 70, to correspondto the ratchet teeth of the gear portion 78. The W pawl 80 is axiallysupported by a pin 82 formed on the V gear 66 at a position displacedrelative to the axial center of the torsion shaft 32 so that the W pawl80 is able to swing around an axis parallel to the torsion shaft 32. Thestructure is such that the W pawl 80, by the swinging movement thereof,contacts or moves away from the inner peripheral portion of the gearportion 78, and by one end of the W pawl 80 moving to approach theproximity of the inner peripheral portion of the gear portion 78, the Wpawl 80 meshes with the ratchet teeth formed on the inner peripheralportion of the gear ring 70. In this meshed state, if the V gear 66 isrotating in the pull out direction then the rotation force of the V gear66 in the pull out direction is transmitted through the W pawl 80 to thegear ring 70, and the gear ring 70 is rotated in the pull out direction.

Also, an inertial mass 84, serving as a rotation detection member, isprovided at the side of W pawl 80 in the radial direction of the gearring 70. The inertial mass 84 is supported by a pair of retentionportions 86 that are formed on the V gear 66, such that the inertialmass 84 is able to swing within a predetermined range substantiallyalong the circumferential direction of the V gear 66, and it isstructured such that the inertial mass 84 that has been swung in thelock activation direction, which is one of the circumferentialdirections of the V gear 66, presses the W pawl 80, swings the W pawl80, and meshes the W pawl 80 with the inner peripheral portion of thegear portion 78.

Furthermore, one end of a return spring 88 is anchored to the inertialmass 84. The return spring 88 is provided with a fixing portion 90formed into a coil-shaped. The fixing portion 90 is anchored to a fixingpin 92 formed on the V gear 66. The return spring 88 is a spiral coilspring with one end side thereof suitably bent, biasing the inertialmass 84 in a swing direction that is the opposite direction to thedirection of swing of the inertial mass 84 when pressing the W pawl 80and swinging the W pawl 80 (this being the lock activation direction).

Furthermore, a restriction weight 94, serving as a restriction unit, isprovided at the opposite side of the inertial mass 84 to that of the Wpawl 80. The restriction weight 94 is provided such that the position ofthe center of gravity thereof is displaced in a rotational radialdirection to the outside from the axial center of the spool 20 (thecenter of rotation), (or in other words, it is preferable to set theposition of the center of gravity of the restriction weight 94 as farfrom the axial center of the spool 20 as possible). An elongated hole 96is formed in the restriction weight 94. The elongated hole 96 isintruded into by a circular column shaped support pin 98 that is formedon the V gear 66. The internal width dimension of the elongated hole 96is just slightly greater than the external diameter of the support pin98, and, therefore, the restriction weight 94 is rotatable about thesupport pin 98, and also restriction weight 94 is able to slide in theradial direction of the V gear 66 up to the point when the support pin98 contacts with the end portions in the length direction of theelongated hole 96.

There is also a contact surface (an abut surface) 100 formed on therestriction weight 94. There is an engagement block 102, serving as aprevention member, formed on the V gear 66 to correspond to the contactsurface 100. A portion of the outer periphery of the engagement block102 is an engagement surface 104, and when the above support pin 98 isin the state of being positioned to one end in the length direction ofthe elongated hole 96 the restriction weight 94 that is in a specificrotation position about the support pin 98 is in a non contactingposition to the inertial mass 84, and the contact surface 100 contactswith the engagement surface 104. In such a contact state of the contactsurface 100 to the engagement surface 104, rotation of the restrictionweight 94 in one of the directions about the support pin 98 isprevented.

However, if the restriction weight 94 slides up to a position where thesupport pin 98 is positioned at the other end in the longitudinaldirection of the elongated hole 96, the opposing state of the contactsurface 100 and the engagement surface 104 is eliminated, and therestriction weight 94 is able to rotate in the one direction about thesupport pin 98 up to where the restriction weight 94 attains a contactposition where the contact surface 100 is positioned in the vicinity ofan engagement surface 106 formed on the engagement block 102 to theoutside in the radial direction of the V gear 66 from the engagementsurface 104.

An interfering portion 108 is also formed on the restriction weight 94.When the restriction weight 94 has attained the above contact position,the interfering portion 108 is able to contact with a contact portion110 that is formed on the restriction weight 94 side of the inertialmass 84. In this state, if the inertial mass 84 attempts to swing in thelock activation direction then the interfering portion 108 contacts thecontact portion 110 and interferes therewith, and restricts swinging ofthe inertial mass 84 in the lock activation direction. Furthermore, theend of the return spring 88 which is on the opposite side of the fixingportion 90 to the end described above, is anchored at the restrictionweight 94, biasing the restriction weight 94 about the support pin 98toward the other side, and biasing the restriction weight 94 toward theposition where the support pin 98 is positioned to one end in thelongitudinal direction of the elongated hole 96.

There is a friction spring 112, serving as an engaging member, providedon the gear ring 70. The friction spring 112 is provided with a body114. The body 114 is basically a ring shape, but has a portion that isnot continuous at one location in the circumferential direction, therebybeing substantially a C-shape. The internal diameter dimension of thebody 114 is formed to be about the same as, or slightly smaller than,the external diameter dimension of the gear ring 70, and the body 114 isfitted over an outer peripheral portion of the gear ring 70, against thespring force of the body 114. The body 114 is able to rotate coaxiallyrelative to the gear ring 70, but presses the outer peripheral portionof the gear ring 70 due to its own spring force, and, unless an externalforce acts on the friction spring 112 to hinder rotation thereof, thebody 114 (friction spring 112) rotates integrally with the gear ring 70.Furthermore, there is a pressing portion 116 extending outside in theradial direction of the body 114 from one end thereof in thecircumferential direction.

Also, there is a substantially ring-shaped friction ring 118 mounted toan outer peripheral portion of the gear ring 70. The friction ring 118is formed with an internal diameter dimension that is larger than theexternal diameter dimension of the gear ring 70. There is one, or plural(three in the present exemplary embodiment), engagement claw(s) 120formed at predetermined intervals around the circumferential directionof the friction ring 118. Annular engagement grooves 122 are formed tothe low wall 72, corresponding to these engagement claws 120 and formedto be continuous in at least a predetermined region along an outerperipheral portion of the low wall 72. The engagement claws 120 fit intothe annular engagement grooves 122, and the engagement claws 120, andtherefore the friction ring 118, are able to relatively rotate coaxiallywith respect to the gear ring 70 within the confines of the annularengagement grooves 122 formed along the outer peripheral portion of thelow wall 72.

In the state in which the friction ring 118 is mounted to the outerperipheral portion of the low wall 72 of the gear ring 70, there is aspace, formed between the outer peripheral portion of the gear ring 70and the internal peripheral portion of the friction ring 118, thatprovides a separation that is the same as, or greater than, thethickness of the friction spring 112, and body 114 of the frictionspring 112 is accommodated within this space.

There is a sensor gear 124 provided at the sensor cover 64 side of the Vgear 66. The sensor gear 124 is provided with a body 126. The torsionshaft 32 passes through, coaxial to the body 126, and the body 126 isrotatably axially supported by the torsion shaft 32. One end of a returnspring 128 is anchored to a portion of the sensor gear 124. The returnspring 128 is a tension coil spring, and the other end of the returnspring 128 is anchored to the sensor cover 64, biasing the sensor gear124 in the take up direction when the sensor gear 124 has been rotatedin the pull out direction around the torsion shaft 32.

There is a window portion 130 formed in the body 126 of the sensor gear124. The window portion 130 passes through at a portion of the body 126in the spool 20 axial direction and radial direction. There is a springseat 132 provided at the inside of the window portion 130. The springseat 132 is provided integrally to the sensor gear 124, in a state ofbeing displaced further to the V gear 66 side of the sensor gear 124than the end face on the sensor cover 64 side of the body 126. Acircular column shaped boss 134 is formed so as to protrude toward thesensor cover 64 side from the spring seat 132, and a coil portion of aspiral coil spring 136 is fitted over the boss 134. One end of thespiral coil spring 136 is anchored to an anchor portion 138 provided onthe spring seat 132.

In contrast, the other end of the spiral coil spring 136 extends in thedirection toward the side of the spring seat 132. A portion in thecircumferential direction of the main body of the above friction ring118 is cut-away, corresponding to the other end of the spiral coilspring 136. An housing portion 140 is provided at this cut-away portion.The housing portion 140 is provided with a pair of side walls 142,144that mutually oppose each other along the circumferential direction ofthe friction ring 118. These side walls 142,144 are connected togetheron the inside thereof in the radial direction of the friction ring 118by a peripheral wall 146, therefore there is a recessed shaped portionformed that is open facing to the outside in the radial direction of thefriction ring 118. The other end of the spiral coil spring 136, on the Vgear 66 of the peripheral wall 146, and the pressing portion 116 intrudeinto the housing portion 140.

A long pressing portion 148 is formed at the body 126 of the sensor gear124 facing toward the V gear 66 side. A shaft 150 is formed to protrudefrom an end portion at the other side of the pressing portion 148 to theside of the V gear 66, and an interlocking pawl 152 is axially supportedby the pressing portion 148 so as to be able to pivot around an axisthat is parallel to (in the same direction as) the axial direction ofthe torsion shaft 32. The interlocking pawl 152, by pivoting, contactsor moves away from the above outer peripheral portion of the V gear 66,and in the state in which the interlocking pawl 152 approaches andengages with the outer peripheral portion of the V gear 66, if the Vgear 66 is rotated in the pull out direction, the rotation of the V gear66 in the pull out direction is transmitted to the sensor gear 124through the interlocking pawl 152, and the sensor gear 124 rotates withthe V gear 66 in the pull out direction.

There is an engaging pin 154 formed to protrude from the face of theinterlocking pawl 152 on the sensor cover 64 side. There is a pressingportion 156, protruding to the outside in the radial direction from anouter peripheral portion of the above friction ring 118 andcorresponding to the engaging pin 154. The pressing portion 156 is bentaround, at a middle portion in the longitudinal direction thereof,toward the V gear 66 side. The distal end side of the pressing portion156 from the bent portion in longitudinal direction middle portion ofthe pressing portion 156, faces the engaging pin 154 along the rotationcircumferential direction of the gear ring 70, and when the frictionring 118 rotates in the pull out direction and the pressing portion 156engages with the engaging pin 154, the pressing portion 156 pushes upthe interlocking pawl 152, through the engaging pin 154, and theinterlocking pawl 152 meshes with the V gear 66.

Furthermore, an acceleration sensor 158 is provided below theinterlocking pawl 152, as shown in FIG. 2. There is a case shapedhousing portion 160 formed on the sensor holder 62 corresponding to theacceleration sensor 158, the housing portion 160 being open to thesensor cover 64 side, and at least a portion of the acceleration sensor158 is accommodated in the housing portion 160. The acceleration sensor158 is provided with a base 162. The base 162 is formed overall in aflat plate shape, with the thickness direction thereof in the verticaldirection. There is a curved surface formed on the top face of the base162, the curved surface opening toward the top, and a hard ball 164,serving as an inertial body, is disposed on top of the curved surface. Asensor pawl 166 is provided above the hard ball 164.

The sensor pawl 166 is pivotally axially supported at the top edge of avertical wall 168 that extends upward from one portion of the outerperiphery of the base 162, and the sensor pawl 166 is pushed upwards bythe hard ball 164 rolling on the curved surface of the base 162. By thesensor pawl 166 being pushed up by the hard ball 164 the sensor pawl 166contacts with the interlocking pawl 152 shown in FIG. 1 and pivots theinterlocking pawl 152 so as to push it upwards. At the pivoting side ofthe interlocking pawl 152, which has been pivoted by the engagement withthe sensor pawl 166, is disposed the above described V gear 66, and dueto this the interlocking pawl 152 meshes with the V gear 66.

The lock mechanism 60, as shown in FIG. 2, is provided with a lock pawl170, serving as a lock member. The lock pawl 170 is provided with a pairof shafts 172. The axial direction of the shafts 172 is a directionparallel to (in the same direction as) the axial direction of the spool20, and one of the shafts 172 is pivotally axially supported in a shaftreceiving hole (omitted in the figure) formed in the leg plate 18, andthe other of the shafts 172 is pivotally axially supported in a shaftreceiving hole 174 formed in the gear case 52. There is a pawl portion176 formed on one of the shafts 172.

The pawl portion 176 is a plate shaped member that has a thicknessdirection that is in the axial direction of the shaft 172, and ratchetteeth are formed on a portion of the outer periphery of the pawl portion176. A lock base 178 is provided at the side of the pawl portion 176that is along the pivoting radial direction of the shaft 172. The lockbase 178 is provided with an insertion fit portion 180. The insertionfit portion 180 is formed in a circular column shape, and fits into aportion at the corresponding end of the through hole 24 of the spool 20so as to be rotatable coaxially relative to the spool 20.

The insertion portion 180, and consequently the lock base 178, is passedthrough coaxially in a rotation fixed state by the torsion shaft 32, androtates integrally and coaxially with respect to the torsion shaft 32. Aratchet portion 182 is formed integrally to the insertion portion 180 atthe leg plate 16 side thereof. The ratchet portion 182 is formed to becoaxial with respect to the insertion portion 180, and there are ratchetteeth formed intermittently on a portion of the outer periphery of theratchet portion 182.

In the above lock pawl 170, the ratchet teeth of the pawl portion 176mesh with the ratchet teeth of the ratchet portion 182 by the pivotingof the shaft 172 in the take up direction. In the meshed state of thepawl portion 176 with the ratchet portion 182, the rotation of theratchet portion 182, and consequently the rotation of the lock base 178,is restricted in the pull out direction. The structure is such that thepressing portion 148 of the sensor gear 124 shown in FIG. 1 correspondswith the pawl portion 176, and when the body 126 of the sensor gear 124rotates in the pull out direction, the pressing portion 148 presses thepawl portion 176, and the lock pawl 170 is pivoted in the take updirection.

Operation and Effect of the First Exemplary Embodiment

Next, explanation will be given of the operation and the effect of thepresent webbing retracting device 10.

In the present webbing retracting device 10, when, in the state in whichthe webbing belt 26 is taken up on the spool 20, the webbing belt 26 ispulled to the distal end side against the biasing of the spiral spring36, then as the webbing belt 26 is gradually pulled out the spool 20rotates in the pull out direction.

In such a manner the pulled out webbing belt 26 is placed around thebody of an occupant and, for example, by retaining a tongue plateprovided in an intermediate portion in the lengthwise direction of thewebbing belt 26 in a buckle device provided at the side of a vehicleseat, the fastened state is arrived at in which the body of the occupantwears the webbing belt 26, and the body of an occupant is restricted bythe webbing belt 26. In such a state in which the webbing belt 26 isfastened, when a vehicle is in a state of rapid deceleration, the hardball 164 consequently rolls, and the sensor pawl 166 is pushed up by thehard ball 164. The sensor pawl 166 pushed up in such a manner, engageswith the interlocking pawl 152 of the sensor gear 124, so as to push upthe interlocking pawl 152. In so doing the interlocking pawl 152 mesheswith the V gear 66.

When the body of an occupant moves in a direction substantially towardthe front of the vehicle, by the inertia as the vehicle decelerates, thewebbing belt 26 is suddenly pulled by the body of the occupant. In thismanner, by the webbing belt 26 being suddenly pulled, rotational forceis suddenly applied to the spool 20 in the pull out direction. Inprinciple, by the spool 20 rotating in the pull out direction, thetorsion shaft 32, and consequently the V gear 66, rotates in the pullout direction, and W pawl 80 and the inertial mass 84 rotate with the Vgear 66 in the pull out direction.

However, when the spool 20 is rotated suddenly in the pull outdirection, as above, the inertial mass 84 does not rotate and attemptsto maintain its position, due to inertia, and by doing so, the inertialmass 84 relatively swings with respect to the V gear 66 against thebiasing force of the return spring 88. When the inertial mass 84 swingsrelative to the V gear 66, from the state shown in FIG. 3, the inertialmass 84 presses the W pawl 80 and swings the W pawl 80, and in doing so,as shown in FIG. 4, one end of the W pawl 80 is moved into the vicinityof an inner peripheral portion of the gear ring 70, and meshes with theratchet teeth formed on an inner peripheral portion of the gear ring 70.

By the meshing of the W pawl 80 with the gear ring 70, the rotationalforce of the spool 20 is transmitted through the torsion shaft 32, the Vgear 66 and the W pawl 80 to the gear ring 70, and the gear ring 70together with the V gear 66 rotates in the pull out direction. Byrotation of the gear ring 70 in the pull out direction, the frictionspring 112 that is pressed by a biasing force against the outerperipheral portion of the gear ring 70 rotates in the pull out directionwith the gear ring 70.

In doing so, when the friction spring 112 rotates by a predeterminedrotational angle in the pull out direction, the pressing portion 116presses the side wall 142 and rotates the friction ring 118 in the pullout direction. By rotation of the friction ring 118 in the pull outdirection, the pressing portion 156 of the friction ring 118 approachesthe vicinity of the engaging pin 154, presses the engaging pin 154, andpushes up the interlocking pawl 152. In doing so the interlocking pawl152 meshes with the V gear 66.

When the interlocking pawl 152 meshes with the V gear 66, as describedabove, the rotational force of the spool 20 in the pull out direction istransmitted through the torsion shaft 32, the V gear 66 and theinterlocking pawl 152 to the sensor gear 124, and due to this the sensorgear 124 is rotated in the pull out direction.

When the sensor gear 124 rotates by a certain angle in the pull outdirection against the biasing force of the return spring 88, thepressing portion 148 provided on the sensor gear 124 presses the pawlportion 176 of the lock pawl 170, and the pawl portion 176 is pivotedabout the shaft 172. When the pawl portion 176 pivots in such a mannerabout the shaft 172, the pawl portion 176 meshes with the ratchetportion 182 of the lock base 178, and rotation of the lock base 178, andconsequently of the spool 20, is restricted in the pull out direction.Due to this, the body of an occupant, which is trying to inertially movein a direction that is substantially the forward direction of thevehicle, may be held, restricted with certainty.

When the insertion through hole 22 in the state in which the webbingbelt 26 is pulled out, is rotated in the take up direction by thebiasing force of the spiral spring 36, the webbing belt 26 is taken upand accommodated on an outer peripheral portion of the insertion throughhole 22 from base end side in the longitudinal direction of the webbingbelt 26. Here, the insertion through hole 22 initiates rotation in thismanner in the take up direction, and the V gear 66 follows the rotationof the insertion through hole 22 and initiates rotation in the take updirection. When the V gear 66 rotates in the take up direction above apredetermined acceleration (rotational angular acceleration), rotationlag occurs of the restriction weight 94 in the take up directionrelative to the V gear 66 due to inertia, and the restriction weight 94attempts to rotate in the pull out direction relative to the V gear 66against the biasing force of the return spring 88. In doing so, therestriction weight 94 slides up to the point where the support pin 98changes a position from a position at one end in the longitudinaldirection of the elongated hole 96 to a position at the other endthereof. By the sliding of the restriction weight 94 in such a manner,the opposing state of the contact surface 100 to the engagement surface104 is eliminated.

Furthermore, since the position of the center of gravity of therestriction weight 94 is distanced from the axial center of the spool20, and consequently from the axial center of the V gear 66 (center ofrotation), the restriction weight 94 is sensitive to rotation of the Vgear 66 and reacts thereto by attempting to fly out toward the outsidein the rotational radial direction of the V gear 66. Therefore, theopposing state of the contact surface 100 to the engagement surface 104has been eliminated, and, when furthermore the V gear 66 rotates in thetake up direction, due to this centrifugal force, a portion of therestriction weight 94 that is to the take up direction side with respectto the support pin 98 moves toward the outside in the rotation radialdirection of the V gear 66. In doing so, as shown in FIG. 5, therestriction weight 94 pivots about the support pin 98 up to a positionin which the contact surface 100 is in the vicinity of the engagementsurface 106, and attains a contact position. In this way, by thepivoting of the restriction weight 94, the interfering portion 108approaches the contact portion 110 of the inertial mass 84.

In the state in which the insertion through hole 22 is rotating in thetake up direction, the restriction weight 94 is maintained in thecontact position by the centrifugal force of the V gear 66. When thetaking up of the webbing belt 26 is completed by the insertion throughhole 22, let us suppose that as a reaction to the completion of take upthe insertion through hole 22 is suddenly rotated, by a slight amount,in the pull out direction. In such a case, it is possible for the V gear66, as well as the insertion through hole 22, to be suddenly rotated, bya slight amount, in the pull out direction.

In such a case, acceleration occurs in the pull out direction on the Vgear 66, in the opposite direction to the direction up to now, and alongwith this, the restriction weight 94 attempts to move in the take updirection relative to the V gear 66. However, in a state of therestriction weight 94 being positioned at an arrived position, the sideend portion of the restriction weight 94 that is to the side that isfurther in the take up direction than the contact surface 100 is incontact with the engagement block 102, preventing movement of therestriction weight 94 in the take up direction or in a direction thatincludes the take up direction, and the restriction weight 94 ismaintained in state of being in the position that has been arrived at.

Furthermore, as described previously, when a great degree ofacceleration occurs at the V gear 66 in the pull out direction,rotational lag occurs in the inertial mass 84 that attempts to maintainits position due to inertia, and the inertial mass 84 hence swings inthe take up direction relative to the V gear 66. Here, when the inertialmass 84 swings, as described above, the inertial mass 84 pushes the Wpawl 80 up, and thereby the W pawl 80 meshes with the ratchet teeth atan inner peripheral portion of the gear portion 78.

However, in the state, in the current arrived at state, if the inertialmass 84 attempts to swing, the interfering portion 108 is in contactwith the contact portion 110, and swinging of the inertial mass 84 isrestricted. Therefore, in this case, the inertial mass 84 does not pushup the W pawl 80, and the W pawl 80 does not mesh with the ratchet teethof an inner peripheral portion of the gear portion 78.

In this way, in the present webbing retracting device 10, when taking upof the webbing belt 26 by the insertion through hole 22 is completed, itis effectively prevented that the W pawl 80 meshes with the ratchetteeth of the gear portion 78, and as a result, a so-called “end-lockstate” of the webbing retracting device 10 occurs.

Furthermore, as described above, after the swinging of the inertial mass84 has been restricted, the restriction weight 94 rotates in the take updirection around the support pin 98 due to the biasing force of thereturn spring 88, and also the restriction weight 94 slides up to theposition such that the support pin 98 is at one end in the longitudinaldirection of the elongated hole 96, and in doing so, the restrictionweight 94 returns to a non contact position with the inertial mass 84.In this way, by the restriction weight 94 returning to a non contactposition, restriction, of the swinging of the inertial mass 84, isreleased.

In this manner, in the state in which the restriction weight 94 is in anon contact position, if the V gear 66 suddenly rotates in the pull outdirection, centrifugal force also acts on the restriction weight 94.However, even if the V gear 66 rotates suddenly in the pull outdirection, the restriction weight 94 is not able to slide in such a waythat the position of the support pin 98 changes from one end in thelongitudinal direction of the elongated hole 96 to the other endthereof. Therefore, in such a case, the opposing state of the contactsurface 100 with the engagement surface 104 is not eliminated, and whenthe restriction weight 94 attempts to pivot about the support pin 98,the engagement surface 104 contacts with the contact surface 100, andpivoting of the restriction weight 94 is prevented. In this way, even ifthere is sudden rotation of the V gear 66, if that rotation is in thepull out direction, the restriction weight 94 is not able to move fromthe non contact position to the arrived position. Therefore, in thisstate, it is not possible that the interfering portion 108 contacts withthe contact portion 110 and there is restriction of swinging of theinertial mass 84.

That is to say, in the present webbing retracting device 10, withoutimpeding the function of locking the insertion through hole 22 whenthere is rapid deceleration, the webbing retracting device 10 such asthe above can prevent an “end-lock state”.

Also, since the present webbing retracting device 10 is configured toactuate the mechanism to prevent entering into an end-lock state byusing the rotational force of the V gear 66 and centrifugal force, themechanism for preventing end-lock may be made compact.

Furthermore, in the present webbing retracting device 10, each of thecomponents of the mechanism to prevent entering into an end-lock stateare all attached to the V gear 66 inside the gear portion 78. Therefore,even though the above superior effect may be achieved, the webbingretracting device 10 is prevented from increasing in size and it may beextremely effectively restricted.

Further, in the present webbing retracting device 10, as describedabove, since it is configured such that the W pawl 80 and the fixingportion 90 are both biased by the return spring 88, the number ofcomponents may be reduced when compared with a configuration in whichthe W pawl 80 and the restriction weight 94 are each biased by separatebiasing member. Along with this reduction there is a reduction in thenumber of component assembly processes. In doing so, a reduction in costmay be achieved and also a large contribution may be made to preventionor suppression of an increase in size of the present webbing retractingdevice 10.

Second Exemplary Embodiment Configuration of the Second ExemplaryEmbodiment

In FIG. 6 a configuration of relevant portions of a webbing retractingdevice 200 according to a second exemplary embodiment of the presentinvention is shown through an exploded perspective view, and in FIG. 7 aconfiguration of relevant portions of the webbing retracting device 200is shown through a front view.

The webbing retracting device 200 according to the present exemplaryembodiment is substantially of the same configuration as the above firstexemplary embodiment, but differs in the following points.

In the webbing retracting device 200, in the rotation detectionmechanism 68, a circular column engagement pin 80A is integrally formedat the other end of the W pawl 80, and the engagement pin 80A projectsfrom the W pawl 80 toward the opposite side to that of the V gear 66.

There is an engagement hole 84A formed through a outer peripheralportion of the inertial mass 84 at the take up direction side, and theengagement hole 84A is open to the outer periphery of the inertial mass84, and is a elongated hole along the outer periphery of the inertialmass 84. The engagement pin 80A of the W pawl 80 inserts into theengagement hole 84A. When the W pawl 80 is swung by the inertial mass 84swinging in the lock activation direction, the engagement pin 80Acontacts with one end of the engagement hole 84A When the W pawl 80 isswung by the inertial mass 84 swinging in the direction opposite to thelock activation direction, the engagement pin 80A contacts with theother end of the engagement hole 84A. Therefore, the swinging range ofthe W pawl 80 and the swinging range of the inertial mass 84 is made tobe a suitable range.

Instead of the return spring 88 in the above first exemplary embodiment,one end of a compression coil spring 202, serving as additional biasingmember, is anchored to the inertial mass 84, and the other end of thecompression coil spring 202 is anchored to the V gear 66. Thecompression coil spring 202 biases the inertial mass 84 in the directionthat is opposite to the lock activation direction.

There is a triangular cross-section lock groove 204, serving as aportion to be restricted, formed through an outer peripheral portion ofthe inertial mass 84 on the pull out direction side, and the lock groove204 is open to the outer periphery of the inertial mass 84.

The restriction weight 94 functions as a moving member configuring arestriction unit. There is no elongated hole 96 or contact surface 100of the above first exemplary embodiment provided at the restrictionweight 94, and there is no support pin 98 of the above first exemplaryembodiment provided at the V gear 66.

There is a substantially triangular cross-section engagement groove 206,serving as an engagement portion, formed through the restriction weight94, and there is, formed at the spool 20 axial center side of theengagement groove 206, an opening portion 206A that opens the engagementgroove 206 to the outer periphery of the restriction weight 94, a firstfacing surface 206B that is on the take up direction side of the openingportion 206A, and a second facing surface 206C that is on the firstfacing surface 206B take up direction side, but further to the spool 20outer peripheral side of than the first facing surface 206B.

The engagement block 102 of the V gear 66 is substantially triangular inshape, and, on the spool 20 axial center side edge of the engagementblock 102, there are formed a first engaging face 102A on the pull outdirection side, and a second engaging face 102B that is at the take updirection side of the first engaging face 102A and more to the outerperipheral side of the spool 20 than the first engaging face 102A. Theengagement block 102 is inserted within the engagement groove 206, andthe restriction weight 94 is disposable in: a non contact portion whendisposed to the spool 20 axial center side, in which the side face onthe take up direction side of the engagement groove 206 is in contactwith the side face on the take up direction side of the engagement block102 (in the non contact position when the first facing surface 206Bfaces (engages) the first engaging face 102A then the second facingsurface 206C also faces (engages) the second engaging face 102B); and,as shown in FIG. 9, a contact position when disposed to the spool 20outer peripheral side in which the side face on the pull out directionside of the engagement groove 206 contacts the side face on the pull outdirection side of the engagement block 102 (in the contact position thefirst engaging face 102A faces (intrudes into) the opening portion 206A,and also the first facing surface 206B faces (engages) the secondengaging face 102B).

One end of a return spring 208, serving as a biasing member, is anchoredto the restriction weight 94, and the return spring 208 is a spiral coilspring with a coil shaped fixing portion 208A formed thereon. The fixingportion 208A is anchored to a fixing pin 210 formed on the V gear 66,and the other end of the return spring 208 is anchored to the V gear 66.In doing so, the return spring 208 biases the restriction weight 94 fromthe contact position in the direction toward the non contact position,and the restriction weight 94 is disposed in the non contact position.

There is a circular shaft shaped rotation shaft 212 provided at a takeup direction side edge portion of the restriction weight 94, and therotation shaft 212 protrudes from the restriction weight 94 to the Vgear 66 side thereof.

There is a substantially circular ring plate shaped lever 214, servingas a restriction member configuring the restriction unit, rotationallysupported between a pull out direction side edge portion of the inertialmass 84 and a take up direction side edge portion of the restrictionweight 94 at the V gear 66. A rotation hole 216 is formed through thelever 214 at a portion to the restriction weight 94 side thereof. Therotation hole 216 is a elongated hole, with the rotation shaft 212 ofthe restraint weight 94 passing therethrough, and the rotation shaft 212is disposed to the inertial mass 84 end side of the rotation hole 216when the restriction weight 94 is disposed in the non contact position,and the lever 214 is disposed in the non contact position. Furthermore,when the restriction weight 94 moves from the non contact position tothe contact position, the rotation shaft 212 moves to the restrictionweight 94 side end of the rotation hole 216, and by rotation of thelever 214 the lever 214 is disposed in the contact position (see FIG.9).

A rectangular plate shaped hook 218, serving as a restriction portion,is integrally formed to an inertial mass 84 side portion of the lever214, and the hook 218 protrudes from the lever 214 toward the oppositeside to that of the V gear 66. The hook 218 is separated from the lockgroove 204 of the inertial mass 84 when the lever 214 is disposed in thenon contact position, and the hook 218 intrudes into the lock groove 204when the lever 214 is disposed in the contact position, and the swingingof the inertial mass 84 in the lock activation direction is restrictableby the engagement (contact) of the hook 218 with the lock groove 204(see FIG. 9).

Here, when the body of an occupant moves in a direction substantially tothe front of a vehicle due to inertia as the vehicle decelerates,suddenly pulling the webbing belt 26, the spool 20 suddenly rotates inthe pull out direction, and the V gear 66 rotates suddenly in the pullout direction, together with the W pawl 80, the inertial mass 84, andthe lever 214. However, due to inertia, the inertial mass 84 does notrotate with respect to the V gear 66, attempts to maintain its position,and the inertial mass 84 swings relative to the V gear 66 against thebiasing force of the compression coil spring 202. In doing so, theinertial mass 84 swings relative to the V gear 66, from the state shownin FIG. 7, and the inertial mass 84 presses the W pawl 80 and swings theW pawl 80, and due to this, as shown in FIG. 8, one end of the W pawl 80approaches the vicinity of an inner peripheral portion of the gear ring70, and meshes with the ratchet teeth formed on the inner peripheralportion of the gear ring 70.

When the webbing belt 26 is taken up on the outer peripheral portion ofthe spool 20 and the spool 20 is rotated in the take up direction by thebiasing force of the spiral spring 36, then the V gear 66 rotates in thetake up direction together with the W pawl 80, the inertial mass 84 andthe lever 214. When the V gear 66 rotates in the take up direction withgreater than a predetermined acceleration (angular velocity) then, dueto inertia, a rotation lag is generated of the restriction weight 94relative to the V gear 66, and the restriction weight 94 swings relativeto the V gear 66 against the biasing force of the return spring 208, andalso the restriction weight 94 moves to the outer peripheral side of theV gear 66 due to centrifugal force. By doing so, as shown in FIG. 9, therestriction weight 94 moves from the non contact position to the contactposition, and, the rotation of the lever 214 from the non contactposition to the contact position, thereby the hook 218 of the lever 214intrudes into the lock groove 204 of the inertial mass 84, and swingingof the inertial mass 84 toward the lock activation direction isrestricted. Furthermore, in the state of the spool 20 rotating in thetake up direction, the restriction weight 94 maintains its contactposition due to centrifugal force.

When the spool 20 has completely taken up the webbing belt 26, the spool20 and the V gear 66 rotate suddenly, and by a very small amount, in thepull out direction, due to rebounding, and acceleration of the V gear 66in the pull out direction occurs, and the restriction weight 94 attemptsto move in the take up direction relative to the V gear 66. At thistime, the restriction weight 94 is disposed in the contact position (theside face on the pull out direction side of the engagement groove 206 ofthe restriction weight 94 contacts with the side face on the pull outdirection side of the engagement block 102), as described above, andmovement of the restriction weight 94 relative to the V gear 66 towardthe take up direction is prevented, and the state is maintained in whichthe restriction weight 94 and the lever 214 are in the contact position,and the state is maintained in which the hook 218 of the lever 214intrudes into the lock groove 204 of the inertial mass 84.

Therefore, as described above, even if a large acceleration of the Vgear 66 in the pull out direction occurs, and the inertial mass 84attempts to swing in the lock activation direction relative to the Vgear 66, the above mentioned intruding of the hook 218 into the lockgroove 204 restricts swinging toward the lock activation direction ofthe inertial mass 84. Therefore, the inertial mass 84 does not push upthe W pawl 80, and the W pawl 80 also does not mesh with the ratchetteeth of the inner peripheral portion of the gear portion 78, therefore,the webbing retracting device 200 can be effectively prevented fromentering the so-called “end-lock state”.

Furthermore, after the restriction weight 94 prevents swinging of theinertial mass 84, the restriction weight 94 and the lever 214 return tothe non contact position from contact position due to the biasing forceof the return spring 208, and restriction of the swinging of theinertial mass 84 is released.

In this manner, in the state in which the restriction weight 94 and thelever 214 are in the non contact positions, if the V gear 66 has beensuddenly rotated in the pull out direction, centrifugal force also actson the restriction weight 94. However, even if the V gear 66 rotatessuddenly in the pull out direction, since the restriction weight 94 isin the non contact position (the first facing surface 206B of therestriction weight 94 is engaged with the first engaging face 102A ofthe engagement block 102, and also the second facing surface 206C of therestriction weight 94 is engaged with the second engaging face 102B ofthe engagement block 102), movement of the restriction weight 94 due tocentrifugal force relative to the V gear 66 and toward the V gear 66outer peripheral side is prevented, and the restriction weight 94 andthe lever 214 are still disposed in the non contact position. Therefore,restriction of the swinging of the inertial mass 84 toward to the lockactivation direction can be prevented.

In the above manner, the present exemplary embodiment is able todemonstrate similar effects to those of the above first exemplaryembodiment, except for the effect due to the return spring 88 biasingboth the W pawl 80 and the restriction weight 94.

Furthermore, the compression coil spring 202 biases the inertial mass 84and also the return spring 88 biases the restriction weight 94.Therefore, each of the inertial mass 84 and the restriction weight 94can be biased to an appropriate amount.

Also, by the movement of the restriction weight 94 from the non contactposition to the contact position, the lever 214 is moved from the noncontact position to the contact position, and swinging of the inertialmass 84 toward the lock activation direction is prevented by the lever214. Therefore, the restriction weight 94 can be moved appropriatelyfrom the non contact position to the contact position by the rotation ofthe V gear 66 toward the take up direction, and also the swinging of theinertial mass 84 toward the lock activation direction can beappropriately restricted by the lever 214.

Third Exemplary Embodiment Configuration of the Third ExemplaryEmbodiment

In FIG. 10 a configuration of relevant portions of a webbing retractingdevice 300 according to a third exemplary embodiment of the presentinvention is shown through an exploded perspective view, and in FIG. 11a configuration of relevant portions of the webbing retracting device300 is shown through a front view.

The webbing retracting device 300 according to the present exemplaryembodiment is substantially of the same configuration as the above firstexemplary embodiment, but differs in the following points.

In the webbing retracting device 300 in the rotation detection mechanism68, just as in the above second exemplary embodiment, there is providedthe engagement pin 80A of the W pawl 80, and engagement hole 84A of theinertial mass 84 and the lock groove 204, and also the compression coilspring 202 spans across between the inertial mass 84 and the V gear 66.

However, the return spring 88, the restriction weight 94, the fixing pin92 of the V gear 66, the support pin 98 and the engagement block 102 ofthe above first exemplary embodiment are not provided.

There is a circular rod shaped support pin 302 integrally provided tothe V gear 66 at a portion in the vicinity of the pull out directionside edge of the inertial mass 84, and the support pin 302 projects fromthe V gear 66.

A lever 304 is provided to the outer periphery of the support pin 302 soas to be able to rotate within a limited range, and the lever 304 is anarm type, being long and substantially rectangular plate shaped.

There is a curved rectangular plate shaped hook 306, serving as arestriction portion, integrally formed to the lever 304 at a portion tothe inertial mass 84 side thereof, and the hook 306 protrudes out fromthe lever 304 to the opposite side to that of the V gear 66. Here, whenthe lever 304 is in the non contact position, in which it is disposed inthe rotational position toward the opposite side to that of the inertialmass 84, the hook 306 is separated from the lock groove 204 of theinertial mass 84, and when the lever 304 is in the contact position, inwhich it is disposed in the rotational position toward the side of theinertial mass 84, the hook 306 intrudes into the lock groove 204, andswinging of the inertial mass 84 toward the lock activation directionrestrictable by the engagement (contact) of the hook 306 to the lockgroove 204.

There is a pair of rectangular plate shaped connecting plates 308,serving as connecting portion, formed integrally on the lever 304 at aportion that is on the opposite side of the inertial mass 84, and thepair of connecting plates 308 project out from the lever 304 to the sidethat is opposite to that of the V gear 66. One of the connecting plates308 is disposed at the center side of the V gear 66, and the other ofthe connecting plates 308 is disposed at the outer peripheral side ofthe V gear 66, and the pair of connecting plates 308 are disposedparallel to each other.

One end of a substantially U-shaped bar friction spring 310, a frictionbiasing member that configures a frictional force generating member, isrotatably supported at the center of the support pin 302, and the otherend of the friction spring 310 is bent around in a U-shape. In adirection from one end of the friction spring 310 to the other endthereof, the friction spring 310 gradually projects out toward thedirection that is the opposite to that of the V gear 66 (see FIG. 14),and the friction spring 310 has a biasing force toward the rotationalaxial direction. A portion at one end of the friction spring 310intrudes at the one of the connecting plates 308 on the outer peripheralside of the V gear 66 and the other of the connecting plates 308 on thecenter side of the V gear 66, being attached to the lever 304, and bydoing so, the friction spring 310 and the lever 304 are able to rotateintegrally with each other.

A substantially rectangular bar shaped cover 312 (cap), serving as acovering member configuring the friction force generation member, ismounted at a portion at the other end of the friction spring 310, and aportion at the distal end of the cover 312 projects as a semi-circularrod shape toward the center side of the V gear 66. As shown in detail inFIG. 15, there is an insertion groove 314 formed at an internal portionof the cover 312, and the insertion groove 314 is open to the V gear 66side. A portion at the other end of the friction spring 310 fits intothe insertion groove 314 of the cover 312, and in doing so the cover 312is fitted to the friction spring 310. AT the cover 312, there are apredetermined number (four in the present exemplary embodiment) ofprojection portions 316 formed at portions on both sides of the openingof the insertion groove 314, and the projection portions 316 project tothe opening side of the insertion groove 314, and friction spring 310 isanchored at the projection portions 316, preventing the cover 312 fromfalling off from the friction spring 310.

A portion at the distal end of the cover 312, as shown in FIG. 14, iscontacted to the V gear 66 side face (flat face) of the gear ring 70 bythe biasing force of the friction spring 310, and when the V gear 66rotates, friction is generated between the portion at the distal end ofthe cover 312 and the V gear 66 side face of the gear ring 70, and thecover 312, the friction spring 310 and the lever 304 rotate integrallytherewith. In doing so, as shown in FIG. 12, when the V gear 66 rotatesin the pull out direction, the lever 304 is disposed in the non contactposition, the hook 306 of the lever 304 separates from the lock groove204 of the inertial mass 84, and, as shown in FIG. 13, when the V gear66 rotates in the take up direction, the lever 304 is disposed in thecontact position, the hook 306 of the lever 304 intrudes into the lockgroove 204.

Furthermore, as described above, the portion at the other end of thefriction spring 310 is inserted in the one connecting plate 308 on theouter peripheral side of the V gear 66 of the lever 304 and the otherconnecting plate 308 on the center side of the V gear 66 of the lever304, and mounted to the lever 304, therefore the lever 304 and thefriction spring 310 do not contact in the directions to the V gear 66side and the opposite side to the V gear 66. In doing so, the biasingforce of the friction spring 310 is not transmitted to the lever 304 inthe rotational axial direction of the friction spring 310 and the lever304, and friction generated between the friction spring 310 and thelever 304 may be suppressed, and impediment to the rotation of thefriction spring 310 and the lever 304 by the biasing force of thefriction spring 310 can be suppressed.

Here, when the body of an occupant moves in a direction substantially tothe front of a vehicle due to inertia as the vehicle decelerates,suddenly pulling the webbing belt 26, the spool 20 suddenly rotates inthe pull out direction, and the V gear 66 rotates suddenly in the pullout direction, together with the W pawl 80, the inertial mass 84, thelever 304, and the friction spring 310 (including the cover 312). Due toinertia, the inertial mass 84 do not rotate with respect to the V gear66, the inertial mass 84 attempts to maintain its position, and theinertial mass 84 swings relative to the V gear 66 against the biasingforce of the compression coil spring 202. Furthermore, as shown in FIG.12, friction is generated between the portion at the distal end of thecover 312 and the V gear 66 side face of the gear ring 70, and by theintegral rotation of the friction spring 310 (including the cover 312)and the lever 304, the lever 304 is disposed in the non contactposition, and the hook 306 of the lever 304 is separated from the lockgroove 204 of the inertial mass 84. In doing so, swinging of theinertial mass 84 relative to the V gear 66 is allowed, and when theinertial mass 84 swings relative to the V gear 66 the inertial mass 84presses the W pawl 80 and swings the W pawl 80, and one end of the Wpawl 80 approached the vicinity of the inner peripheral portion of thegear ring 70, and meshes with the ratchet teeth formed on the innerperipheral portion of the gear ring 70.

However, when the webbing belt 26 is taken up on the outer peripheralportion of the spool 20, and the spool 20 is rotated in the take updirection by the biasing force of the spiral spring 36, the V gear 66rotates in the take up direction, together with the W pawl 80, inertialmass 84, lever 304 and friction spring 310 (including the cover 312).The inertial mass 84 attempts to maintain its position without rotatingwith respect to the V gear 66 due to inertia, and the inertial mass 84attempts to swing relative to the V gear 66 against the biasing force ofthe compression coil spring 202. Furthermore, as shown in FIG. 13,friction is generated between the portion at the distal end of the cover312 and the V gear 66 side face of the gear ring 70, and the frictionspring 310 (including the cover 312) and the insertion groove 314integrally rotate, and the lever 304 is disposed in the contactposition, the hook 306 of the lever 304 intrudes into the lock groove204 of the inertial mass 84. In doing so, swinging of the inertial mass84 relative to the V gear 66 is restricted.

When the spool 20 has completely taken up the webbing belt 26, eventhough the spool 20 and the V gear 66 rotate suddenly, and by a verysmall amount, in the pull out direction, due to rebounding, the lever304 is maintained in the state of being in the contact position, and thehook 306 of the lever 304 is maintained in the state of intrusion intothe lock groove 204 of the inertial mass 84.

Due to this, as described above, even if a large acceleration isgenerated to the V gear 66 in the pull out direction, and the inertialmass 84 attempts to swing in the lock activation direction relative tothe V gear 66 due to inertia, the swinging of the inertial mass 84 inthe lock activation direction is restricted by the above mentionedinsertion of the hook 306 into the lock groove 204. Therefore, theinertial mass 84 does not push up the W pawl 80, and since the W pawl 80does not mesh with the ratchet teeth on the inner peripheral portion ofthe gear portion 78, the webbing retracting device 300 can beeffectively prevented from entering the so-called “end-lock state”.

The present exemplary embodiment may also, by the above, have similareffects to those of the above first exemplary embodiment, except for theeffect of being a mechanism configured for preventing entering theend-lock state by the action of the rotation force and centrifugal forceof the V gear 66 and the effect of biasing both the W pawl 80 and therestriction weight 94 with the return spring 88.

Furthermore, in the present webbing retracting device 300, since themechanism for preventing entering the end-lock state is configured usingthe rotation force of the V gear 66 and the frictional force of thecover 312 and the gear ring 70, the mechanism for preventing enteringthe end-lock state can be made compact.

Also, the lever 304 is moved from the non contact position to thecontact position by the frictional force between the cover 312 and thegear ring 70, and swinging of the inertial mass 84 toward the lockactivation direction is restricted by the lever 304. Therefore, thelever 304 can be moved appropriately from the non contact position tothe contact position by the rotation of the V gear 66 in the take updirection, and also swinging of the inertial mass 84 toward the lockactivation direction can be appropriately restricted by the lever 304.

Furthermore, a portion at the distal end of the cover 312 contacts withthe gear ring 70, and a frictional force is generated between the cover312 and the gear ring 70. Therefore, surface contact may be made betweenthe cover 312 and the gear ring 70, and smooth and stable relativemovement may be made between the cover 312 and the gear ring 70, andgeneration of noise due to the relative movement of the cover 312 andthe gear ring 70 can be suppressed.

In the present exemplary embodiment it is configured such that the cover312 that is attached to a portion at the other end side of the frictionspring 310 and the gear ring 70 are in contact, however, the cover 312does not need to be attached to the portion at the other end side of thefriction spring 310, and it is possible that the other end of thefriction spring 310 can be caused to contact with the gear ring 70.

Fourth Exemplary Embodiment Configuration of the Fourth ExemplaryEmbodiment

In FIG. 16 a configuration of relevant portions of a webbing retractingdevice 400 according to a fourth exemplary embodiment of the presentinvention is shown through an exploded perspective view, and in FIG. 17a configuration of relevant portions of the webbing retracting device400 is shown through a front view.

The webbing retracting device 400 according to the present exemplaryembodiment is configured essentially the same as that of the firstexemplary embodiment, but differs in the following points.

At the rotation detection mechanism 68 in the webbing retracting device400, in the same way as in the second exemplary embodiment, there isprovided the engagement pin 80A of the W pawl 80, and the engagementhole 84A of the inertial mass 84 and lock groove 204, and thecompression coil spring 202 also spans between the inertial mass 84 andthe V gear 66.

However, the return spring 88, the restriction weight 94, the fixing pin92 of the V gear 66, the support pin 98 and the engagement block 102 ofthe above first exemplary embodiment are not provided.

A circular column shaped support pin 402 is integrally provided to the Vgear 66 at the vicinity to the edge portion of the inertial mass 84 atthe pull out direction side, and the support pin 402 protrudes to the Vgear 66 side.

A lever 404 is supported so as to be able to rotate within apredetermined range at the outer periphery of the support pin 402, andthe lever 404 is a slide type lever, formed in a long substantiallyrectangular shape.

There is a curved rectangular plate-shaped hook 406, serving as arestriction portion, integrally formed at a portion on the inertial mass84 side of the lever 404, and the hook 406 projects from the lever 404to the side that is opposite to that of the V gear 66. By the lever 404being disposed in a rotational position that is toward the side that isopposite to the inertial mass 84 side, the hook 406 is separated fromthe lock groove 204 of the inertial mass 84, and, as shown in FIG. 19,by the lever 404 being disposed in a contact position that is arotational position to the inertial mass 84 side, the hook 406 intrudesinto the lock groove 204, and restriction can be made of swinging of theinertial mass 84 toward the lock activation direction by engagement(contact) of the hook 406 to the lock groove 204.

There is a rectangular plate-shaped drive plate 408 integrally formed tothe lever 404 at a portion that is at the opposite side to that of theinertial mass 84, and the drive plate 408 protrudes from the lever 404to the opposite side to that of the V gear 66.

A plate-shaped slider 410, serving as a connecting member configuring afriction force generation member, is provided to the V gear 66 at thepull out direction side of the lever 404. There is a curved rectangularplate-shaped guide protrusion 412, configuring a guide member,projecting from the face on the V gear 66 side of the slider 410, andthe guide protrusion 412 curves along the circumferential direction ofthe V gear 66. The guide protrusion 412 intrudes into a guide hole 414and contacts a sensor holder 62 (see FIGS. 2, 20 and 21), and by theguide protrusion 412 sliding (moving) along the guide hole 414, theslider 410 is able to slide (move) in the circumferential direction ofthe V gear 66.

A drive hole 416, configuring a drive portion, is formed through aportion at the lever 404 side of the slider 410, and the slider 410 andthe lever 404 are connected together by the drive plate 408 of the lever404 being intruded within the drive hole 416 so as to be rotatablemovable therein, and by the slider 410 sliding in the circumferentialdirection of the V gear 66, the lever 404 is made rotatable.

One end of a substantially U-shaped bar friction spring 418, serving asa friction biasing member configuring a friction force generationmember, is rotatably supported at the surface of the slider 410 that ison the opposite side to that of the V gear 66, and the other end of thefriction spring 418 is bent into a substantially U-shape. The frictionspring 418 is disposed such that the portion at the other end side ismore to the opposite side to that of the V gear 66 than the portion atthe one end side, and the friction spring 418 has a biasing force towardthe rotational axial direction. There is a wavy slot-shaped insertiongroove 420 formed at the face of the slider 410 that is on the oppositeside to that of the V gear 66, and a portion at the one end side of thefriction spring 418 is inserted into the insertion groove 420, androtation of the friction spring 418 relative to the slider 410 isprevented. There is a rectangular column shaped support protrusion 422formed at a bottom face of the insertion groove 420, and a portion atthe one end side of the friction spring 418 is supported at a facethereof by the support protrusion 422.

As shown in FIG. 20 and FIG. 21, the other end of the friction spring418 contacts the V gear 66 side face (flat face) of the gear ring 70,due to the biasing force of the friction spring 418, and by thegeneration of frictional force between the other end of the frictionspring 418 and the V gear 66 side face of the gear ring 70, the frictionspring 418 and the slider 410 integrally slide in the V gear 66circumferential direction relative to the V gear 66, and the lever 404rotates. In doing so, as shown in FIG. 18, when the V gear 66 rotates inthe pull out direction, the lever 404 is disposed in the non contactposition, and so the hook 406 of the lever 404 separates from the lockgroove 204 of the inertial mass 84, whereas, when the V gear 66 rotatesin the take up direction, as shown in FIG. 19, the lever 404 is disposedin the contact position and the hook 406 of the lever 404 is insertedinto the lock groove 204.

Here, when the body of an occupant moves in a direction substantially tothe front of a vehicle and due to inertia as the vehicle decelerates,suddenly pulling the webbing belt 26, the spool 20 suddenly rotates inthe pull out direction, and the V gear 66 rotates suddenly in the pullout direction, together with the W pawl 80, the inertial mass 84, thelever 404, the slider 410 and the friction spring 418. Due to inertia,the inertial mass 84 does not rotate with respect to the V gear 66 andattempts to maintain its position, and the inertial mass 84 swingsrelative to the V gear 66 against the biasing force of the compressioncoil spring 202. Furthermore, as shown in FIG. 18, frictional force isgenerated between the other end of the friction spring 418 and the Vgear 66 side face of the gear ring 70, and by friction spring 418 andthe slider 410 sliding in the V gear 66 circumferential directionrelative to the V gear 66, the lever 404 rotates, and the lever 404 isdisposed in the non contact position, and the hook 406 of the lever 404separates from the lock groove 204 of the inertial mass 84. In doing so,the inertial mass 84 becomes able to swing relative to the V gear 66,the inertial mass 84 swings relative to the V gear 66, the inertial mass84 presses the W pawl 80 to swing the W pawl 80, and one end of the Wpawl 80 approaches the vicinity of the inner peripheral portion of thegear ring 70, and meshes with the ratchet teeth formed on the innerperipheral portion of the gear ring 70.

However, when the webbing belt 26 is taken up on the outer peripheralportion of the spool 20, the spool 20 rotates in the take up directionunder the biasing force of the spiral spring 36, and the V gear 66rotates in the take up direction, together with the W pawl 80, theinertial mass 84, the lever 404, the slider 410 and the friction spring418. Therefore, due to inertia, the inertial mass 84 does not rotatewith respect to the V gear 66 and attempts to maintain its position, andthe inertial mass 84 swings relative to the V gear 66 against thebiasing force of the compression coil spring 202. Furthermore, as shownin FIG. 19, a frictional force is generated between the other end of thefriction spring 418 and the V gear 66 side face of the gear ring 70, bythe friction spring 418 and the slider 410 sliding in the V gear 66circumferential direction relative to the V gear 66, the lever 404 isrotated, and the lever 404 is disposed in the contact position. The hook406 of the lever 404 is intruded into the lock groove 204 of theinertial mass 84. In doing so, the swinging of the inertial mass 84relative to the V gear 66 is restricted.

When the spool 20 has completely been taken up the webbing belt 26, evenif the spool 20 and the V gear 66 rotate due to rebounding suddenly by avery small amount in the pull out direction, the lever 404 maintains thestate of being at the contact position, and the hook 406 of the lever404 maintains the state of being intruded into the lock groove 204 ofthe inertial mass 84.

Therefore, as described above, even if a large degree of accelerationoccurs in the V gear 66 toward the pull out direction, and due toinertia, the inertial mass 84 attempts to swing toward the lockactivation direction relative to the V gear 66, due to the abovementioned intrusion of the hook 406 into the lock groove 204, swingingof the inertial mass 84 toward the lock activation direction isrestricted. Therefore, the inertial mass 84 does not push up the W pawl80, and since the W pawl 80 does not mesh with the ratchet teeth of theinner peripheral portion of the gear portion 78, the webbing retractingdevice 400 is effectively prevented from entering into the so-called“end-lock state”.

The present exemplary embodiment may also, by the above, have similareffects to those of the above first exemplary embodiment, except for theeffect of being a mechanism configured for preventing entering theend-lock state by the action of the rotation force and centrifugal forceof the V gear 66, and the effect of biasing both the W pawl 80 and therestriction weight 94 with the return spring 88.

Furthermore, since the mechanism of the webbing retracting device 400for preventing entering into the end-lock state is configured to operatewith the rotation force of the V gear 66 and the frictional forcebetween the friction spring 418 and the gear ring 70, the mechanism forpreventing the end-lock state can be made compact.

Also, the lever 404 is moved from the non contact position to thecontact position by the frictional force between the friction spring 418and the gear ring 70, and swinging of the inertial mass 84 toward thelock activation direction is restrained by the lever 404. Due to this,the lever 404 may be appropriately moved from the non contact positionto the contact position by the rotation of the V gear 66 in the take updirection, and also the swinging of the inertial mass 84 toward the lockactivation direction can be appropriately restricted by the lever 404.

Furthermore, the since the shapes of the lever 404 and the slider 410are simple, the suitability for assembly and the machinability can beimproved, and cost may be reduced.

In the present exemplary embodiment it is configured such that the otherend of the friction spring 418 and the gear ring 70 contact with eachother, however, a portion at the other end side of the friction spring418 may be, as in third exemplary embodiment, attached with a cover 312,and the cover 312 may be made to contact with the gear ring 70.

1. A webbing retracting device comprising: a spool that, by rotation ina take up direction, takes up a longitudinal band-shaped webbing beltfrom a base end side of webbing belt and stores the webbing beltthereon; a rotational body provided so as to be able to rotate relativeto the spool and connected to the spool so as to be able to rotate tofollow rotation of the spool; a lock member that restricts rotation ofthe spool in a pull out direction by activation thereof; a rotationdetection member, provided at the rotational body, that is displacedtoward a predetermined lock activation direction to activate the lockmember when the rotational body rotates in the pull out direction at apredetermined velocity or greater; and a restriction unit, provided atthe rotational body, that restricts displacement of the rotationdetection member toward the lock activation direction due to a reboundby stopping of taking up of the webbing belt to the spool, wherein therestriction unit is activated by centrifugal force generated by therotating of rotational body.
 2. The webbing retracting device accordingto claim 1, further comprising a prevention member that, in a state inwhich the rotational body is rotating in the pull out direction, whichis different from a state in which the rotational body is rotated in thepull out direction caused by the rebound by stopping of taking up of thewebbing belt, prevents restricting, by the restriction unit, of thedisplacement of the rotation detection member toward the lock activationdirection.
 3. The webbing retracting device according to claim 1,wherein: the restriction unit is provided so as to be movable between acontact position, in which the restriction unit is in contact with therotation detection member and is able to restrict displacement of therotation detection member to the lock activation direction, and a noncontact position, which is separated from the contact position and whichallows displacement of the rotation detection member toward the lockactivation direction; and the restriction unit displaces to the contactposition by rotation of the rotational body in the take up direction. 4.The webbing retracting device according to claim 3, wherein therestriction unit in the non contact position is moved to the contactposition by the centrifugal force.
 5. The webbing retracting deviceaccording to claim 3, further comprising a biasing member that biasesthe restriction unit from the contact position toward the non contactposition.
 6. The webbing retracting device according to claim 5, whereinthe biasing member biases the rotation detection member in the oppositedirection to the lock activation direction.
 7. The webbing retractingdevice according to claim 1, further comprising an additional biasingmember that biases the rotation detection member in the oppositedirection to the lock activation direction.
 8. The webbing retractingdevice according to claim 1, wherein the restriction unit comprises: amoving member that is moved by the rebound when taking up of the webbingbelt to the spool stops; and a restriction member that is moved by themovement of the moving member and restricts displacement of the rotationdetection member toward the lock activation direction.